Green synthesis of zero valent colloidal nanosilver targeting A549 lung cancer cell: In vitro cytotoxicity

An eco-friendly green approach was proposed to synthesise stable, cytotoxic colloidal silver nanoparticles (AgNPs) using Momordica charantia (M. charantia) fruit extract. Bioinspired green method adopted for fabrication of AgNPs because of easy, fast, low-cost and benign bioprocess. Phytocomponents played the crucial role in capping, stabilisation and inherent cytotoxic potential of colloidal nanosilver. The physiochemical, crystalline, optical and morphological properties of AgNPs were characterized using UV-vis, FT-IR, XRD, SEM, TEM, EDX and AFM. FT-IR reveals the presence of carbonyl, methyl, polyphenol (flavonoid), primary and secondary amine (protein), carboxyl group, ester as major functional groups over the surface of nanomaterials. Mechanistic pathway for formation and stabilisation of colloidal nanosilver has been discussed. Average crystalline size of AgNPs was found to be 12.55?nm from XRD. TEM shows AgNPs nanosphere with size range 1–13.85?nm. Consistency in spherical morphology was also confirmed through Atomic Force Microscopy (AFM). AFM measurement provided image Rq value 3.62, image Ra 2.47, roughness Rmax 36.4?nm, skewness 1.99 and kurtosis 9.87. The SRB assay revealed substantial in vitro noticeable anti-cancer activity of colloidal nanosilver on A549 and HOP-62 human lung cancer cells in a dose dependent manner with IC50 value of 51.93?µg/ml and 76.92?µg/ml. In addition, M. charantia capped AgNPs were found to be more biocompatible in comparison to M. charantia FE. Our study demonstrated the integration of green chemistry principle in nanomaterials fabrication and focused on the potential use of M. charantia fruit extract as an efficient precursor for biocompatible AgNPs anodrug formulation with improved cytotoxic applications.     

1H, 15N and 13C resonance assignments and monomeric structure of the amino-terminal extracellular domain of epithelial cadherin

Summary E-cadherin is a transmembrane protein that provides Ca²⁺-dependent cell adhesion to epithelial cells. The large majority of the ¹H, ¹⁵N, ¹³C and ¹³CO resonances of a 146-amino acid polypeptide from epithelial (E-) cadherin have been assigned using multidimensional NMR spectroscopy. The structure of the amino-terminal 100 amino acids, corresponding to the first extracellular repeat of E-cadherin [Overduin et al. (1995) Science, 267, 386–389], has been refined. The monomeric state of this isolated domain is demonstrated by light scattering and sedimentation analysis. Seven -strands and two short helices were identified by patterns of NOE cross-peaks, vicinal coupling constants and chemical shift indices. A novel structural motif termed a quasi--helix found in the crystal structure of a neural (N-) cadherin domain [Shapiro et al. (1995) Nature, 374, 327–337] is characterized in detail for the first time by NMR. Slowly exchanging amides were concentrated in the -sheet region and quasi--helix. The -barrel fold of the cadherin domain is topologically similar to the immunoglobulin fold. Comparison of this solution structure to the crystallized dimers of the N-terminal pair of E-cadherin domains [Nagar et al. (1996) Nature, 380, 360–364] and of the homologous single domain of N-cadherin reveals a conserved cadherin fold with minor structural differences, which can be accounted for by differences in metal ligation and oligomeric state.Abbreviations cad extracellular cadherin repeat - CAM cell adhesion molecule - CSI chemical shift index - DTT dithiothreitol - E-cadherin epithelial cadherin - N-cadherin neural cadherin - NOE nuclear Overhauser enhancement - PFG pulsed field gradient - rmsd root-mean-square deviation     

Microbial production of (+)-trans-isochorismic acid

Two methods are described for the preparation of enantiomerically pure (+)-trans-isochorismic acid, an important metabolite of the postchorismate pathway. Both methods can be employed to prepare isotopically labeled isochorismic acid. One of the two methods is suitable to prepare bulk quantities of isochorismic acid using a recombinant strain of Klebsiella pneumoniae 62-1. (c) 1995 John Wiley & Sons, Inc.     

A higher-plant type ζ-carotene desaturase in the cyanobacterium Synechocystis PCC6803

The genomic DNA sequence of Synechocystis was analysed for putative -carotene desaturase genes. Two promising candidates slr0940 and slr0033 were found with similarities to the structurally different -carotene desaturase genes from higher plants and Anabaena, respectively. Only the expression product of the analogue to the plant gene, slr0940, was able to mediate the 2-step desaturation of -carotene via neurosporene to lycopene after complementation of this pathway in Escherichia coli. When enzyme reactions were carried out with this protein, activity was obtained with either -carotene or neuroporene as substrates. The in vitro reaction was inhibited by the pyrimidine derivative J852 which is effective as experimental herbicide in plants. The occurrence of two different types of -carotene desaturases among cyanobacteria and the phylogenetic consequences on chloroplast evolution are discussed.     

TRIM16 controls assembly and degradation of protein aggregates by modulating the p62‐NRF2 axis and autophagy

Sequestration of protein aggregates in inclusion bodies and their subsequent degradation prevents proteostasis imbalance, cytotoxicity, and proteinopathies. The underlying molecular mechanisms controlling the turnover of protein aggregates are mostly uncharacterized. Herein, we show that a TRIM family protein, TRIM16, governs the process of stress‐induced biogenesis and degradation of protein aggregates. TRIM16 facilitates protein aggregate formation by positively regulating the p62‐NRF2 axis. We show that TRIM16 is an integral part of the p62‐KEAP1‐NRF2 complex and utilizes multiple mechanisms for stabilizing NRF2. Under oxidative and proteotoxic stress conditions, TRIM16 activates ubiquitin pathway genes and p62 via NRF2, leading to ubiquitination of misfolded proteins and formation of protein aggregates. We further show that TRIM16 acts as a scaffold protein and, by interacting with p62, ULK1, ATG16L1, and LC3B, facilitates autophagic degradation of protein aggregates. Thus, TRIM16 streamlines the process of stress‐induced aggregate clearance and protects cells against oxidative/proteotoxic stress‐induced toxicity in vitro and in vivo. Taken together, this work identifies a new mechanism of protein aggregate turnover, which could be relevant in protein aggregation‐associated diseases such as neurodegeneration.     

Species-area curve,life history strategies,and succession: a field test of relationships

Changes of species richness along temporal and environmental gradients were investigated. Two data sets were used: a successional sere of old-field plant communities in the Bohemian Karst, and a set of plant communities under various intensities of disturbance in the Krkonoe (Giant) Mts, both in Czechoslovakia. The species richness of a plant community is a spatial phenomenon, and should be described by the species-area relationship (using e.g. the power function S=c\A ^z) rather than by a single number. In the old-field succession, the number of species in very small plots (0.1×0.1 m) tends to increase with successional age while the number of species in larger plots (4×4 m) decreases from the third year of succession. The plant community under the highest rate of disturbance of the Krkonoe Mts data set shows the lowest number of species on small plots and the highest number of species on large plots. The results may be explained using the distinction between founder-and dominance-controlled communities (Yodzis 1978, 1984). In accordance with this theory, the species-area relationship within a community is shaped mainly by the type of competitive interaction and may be predicted on the basis of life-history strategies of constituent species. Disturbance causes a shift from dominance to founder control. On the landscape scale, the species-area relationship is shaped by other factors, and so it is unjustified to extrapolate the relationship outside the range in which it was originally assessed.     

PE_PGRS62 promotes the survival of Mycobacterium smegmatis within macrophages via disrupting ER stress-mediated apoptosis

Mycobacterium tuberculosis, the leading causative agent of tuberculosis, remains one of the most deadly infectious pathogens. PE_PGRS proteins become a new focus as their species specificity in mycobacteria, especially in pathogenic mycobacteria. Despite intensive research, PE_PGRS proteins are still a mysterious aspect of mycobacterial pathogenesis with unknown mechanism. Herein, we focused on a PE_PGRS member from M. tuberculosis, PE_PGRS62, characterized by a surface-exposed protein function in disrupting phagolysosome maturation. Expression of PE_PGRS62 in Mycobacterium smegmatis, a nonpathogenic species naturally deficient in PE_PGRS genes, resulted in enhanced resistance to various in vitro stresses and cellular survival in macrophage. As a consequence, the cytokine profiles of macrophage were disturbed and cell apoptosis were inhibited via decreasing endoplasmic reticulum stress response.